Nghe An: Floods are coming in droves, Ban Ve Hydropower Plant has to release water urgently

According to information from Power Generation Corporation 1 (EVN), the flood started appearing at 4:00 a.m. on July 22 with a flow rate of 583 m³/s, then increased rapidly to 1,500 m³/s at 10:00 a.m. the same day, the lake water level was 189.69 m.

Implementing the order of the Steering Committee for Natural Disaster Prevention - Search and Rescue and Civil Defense of Nghe An province on flood reduction operations for downstream areas, at 4:00 p.m. the same day, the reservoir began to discharge flood control with a flow rate of 508 m³/s through the spillway, combined with discharge through the project of 845 m³/s. The water level of the reservoir at the same time was 191.23 m (the lowest flood level was 191.5 m).

At the peak flood time (2:00 a.m. on July 23), the total water discharge was 3,285 m³/s, the reservoir reduced about 74% of the peak flood flow to reduce flooding downstream.

Ban Ve Hydropower Plant recorded a peak flood in the lake with a flow of 12,800 m3/s, equivalent to a flood frequency of 0.02% (probability of occurring once every 5,000 years). (Photo: EVNGENCO1).

Flood reduction for downstream by retaining 74% of the peak flood flow at the hydroelectric reservoir causes the water level of the reservoir to increase rapidly, gradually shifting the reservoir to an operating mode that ensures the safety of the project.

However, the downstream area is experiencing serious flooding, so the company has reported to the Chairman of Nghe An Provincial People's Committee, requesting to switch from the operation mode to ensure project safety to the abnormal operation mode to limit water discharge downstream, in order to continue to reduce flooding downstream.

This was an exceptionally large flood, exceeding the frequency of the flood test (the flood test of Ban Ve Hydropower Plant has a flow rate of 10,500 m³/s), but the company operated to ensure absolute safety for the headworks, contributing significantly to cutting and reducing floods downstream.

Faced with the risk of major floods, on the evening of July 22, the People's Committee of Nghe An province issued an urgent notice regarding the Ban Ve Hydropower Plant - the largest hydropower project in the North Central region - regulating the reservoir with a large discharge flow.

According to urgent notice No. 604 issued by the Provincial People's Committee at 9:00 p.m. on July 22, the water flow into the upstream of Ban Ve Hydropower Reservoir reached 9,543m³/s, nearly reaching the peak flood flow threshold of 10,500m³/s, equivalent to a flood frequency of 0.02%.

Faced with this situation, Ban Ve Lake has cut down on flooding, currently discharging downstream at a flow rate of 1,727m³/s and is expected to increase rapidly in the coming time.

Ban Ve Hydropower Plant is the largest hydropower project in Nghe An province and the North Central region, with a designed capacity of 320MW, a basin area of more than 8,700km², spanning the communes of Luong Minh, Huu Khuong, Nhon Mai...

In addition to its power generation tasks, Ban Ve also plays a particularly important role in flood regulation, water supply for daily life, production, saltwater intrusion and ensuring water security for the downstream of the Ca River - especially during heavy rains and floods.

PHAM DUY

Source: https://vtcnews.vn/nghe-an-lu-ao-at-tran-ve-thuy-dien-ban-ve-phai-xa-nuoc-gap-ar955884.html